Positioning device for use in radiography

ABSTRACT

An X-ray cassette or a radiographic grid and X-ray cassette is (are) mounted within a device for positioning the cassette or grid and cassette beneath a patient lying upon a bed or other support to enable an X-ray image of a portion of the patient to be taken. The device has a plastics envelope formed of a material that is both substantially radiotranslucent and impervious to water or other biological fluids. This envelope defines first and second envelope sections separated from each other by a common edge. The first envelope section is generally rectangular in configuration and defines an openable pouch in which the X-ray cassette or radiographic grid and X-ray cassette are received. The second envelope section has a stiffening member therein. The second envelope section has its greatest width along the common edge and narrows to a minimum width at its edge furthest from the common edge. The stiffening member within the second envelope section is generally wedge shape in section, whereby the second envelope section has a thickness that tapers from a maximum thickness approximating the thickness of the radiographic grid and X-ray cassette at its greatest width adjacent the common edge to a minimum thickness at the furthest edge.

RELATED APPLICATION

This application claims priority to and the benefit of GB 0206634.8filed Mar. 20, 2002.

BACKGROUND OF THE INVENTION

This invention relates to radiography and to problems encountered inpositioning a patient in relation to X-ray equipment and in relation tophotographic film or digital media adapted for taking an X-ray pictureof a portion of the patient.

Patients that are severely ill or are suffering from spinal or pelvicinjury are often presented to a radiographer lying upon a bed or othersupport. In order that an X-ray image may be taken, the photographicfilm or digital medium, conventionally mounted in an X-ray cassette(together with a radiographic grid when the chest, spine or pelvis areto be imaged) must be positioned beneath the patient so that the patientcan be placed beneath a source of X-rays to enable an X-ray image to betaken through a portion of their body.

Specially adapted beds or supports have previously been provided with ahollowed out section into which the radiographic grid and X-ray cassettemay be inserted while the patient is lying upon the support. However,this is not satisfactory in use since the patient must first betransferred to the special support on which he will not be adequatelysupported at least at the time that the grid and cassette are beinginserted from the side beneath him. Attempts to simply insert the gridand cassette, either alone or within a pouch, from the side and beneaththe patient between an upper and a lower sheet on a conventional bed orsupport have also not proved satisfactory, firstly because of thefriction encountered and secondly because of the jarring effect of theedge of the grid and cassette on the patient's spine or pelvis. X-raycassettes for taking a chest or pelvic X-ray image and associatedradiographic grids are quite substantial. The resultant image hasdimensions of the order of 35 cm×43 cm, the orientation depending uponwhether the image is taken in landscape or portrait format. The grid andcassette are slightly larger but known to radiographers as a “35×43”grid and cassette. The grid and cassette have a thickness of around 25mm.

The patent literature includes a number of proposals for mounting X-raycassettes from or within supports slid into position beneath a patient,but none is ideal. Thus: Wright in U.S. Pat. No. 5,703,925 proposes asupport for an X-ray cassette that in use is positioned between a raisedpatient support platform and smooth flush surface below the patientsupport platform. A spade supports an x-ray cassette and is enabled toslid on this flush surface. Strawder (U.S. Pat. No. 5,226,068) employs asupport to mount an X-ray cassette in a vertical position alongside apatient. The support is generally flat apart from a cavity enabling thecassette to stand upright on edge from the support and a ramp edgeenabling the support to be more easily slid under a patient. Möllerproposes a lifting device in U.S. Pat. No. 5,133,000 to raise a bed toslide an X-ray cassette beneath it. Waerve (U.S. Pat. No. 4,247,778) hasa generally flat X-ray cassette chamber with a rounded leading edge toease its insertion beneath a patient. An X-ray cassette can be movedwithin the chamber to enable an X-ray to be taken vertically through thepatient in one configuration or horizontally through the patient inanother configuration.

SUMMARY OF THE INVENTION

The device of the present invention has been devised with a view toovercoming the problems described above and to enable a radiographicgrid and X-ray cassette to be more readily properly positioned beneaththe appropriate portion of a patient already lying on a bed or othersupport with a minimum of jarring or movement to the spine or pelviswhen inserting the grid and X-ray cassette beneath the patient.

In accordance with a first aspect of the present invention, there isprovided a positioning device for use in radiography to position anX-ray cassette or a radiographic grid and X-ray cassette beneath apatient lying upon a bed or other support to enable an X-ray image of aportion of the patient to be taken; the device comprising: a plasticsenvelope formed of a material that is both substantiallyradiotranslucent and impervious to water or other biological fluids; theenvelope defining first and second envelope sections separated from eachother by a common edge; the first envelope section being generallyrectangular in configuration and defining an openable pouch dimensionedto receive an X-ray cassette or radiographic grid and X-ray cassettetherein; and the second envelope section having a stiffening membertherein, the second envelope section having its greatest width alongsaid common edge and narrowing to a minimum width at its edge furthestfrom said common edge, and the stiffening member within the secondenvelope section being generally wedge shape in section, whereby thesecond envelope section tapers from a maximum thickness approximatingthe thickness of a radiographic grid and X-ray cassette at its greatestwidth adjacent the common edge to a minimum thickness at said furthestedge.

The furthest edge where the second envelope section with its stiffeningmember therein has both its minimum thickness and narrowest width issuitably provided with a handle formed of tape. By separating a topsheet from its under sheet on the bed or support on which the patient islying and inserting the thin and narrow edge between the two sheets, thesecond envelope section may readily be slid beneath the patient untilthe handle may be grabbed from the far side. From that point on, thedevice may be pulled. Forming the envelope of the device from plasticsreduces friction with the sheets. In the preferred arrangement, theplastics envelope is provided with a low-friction varnish coating. As aresult of the wedge shape of the stiffening member, the patient isgradually and almost imperceptibly raised as the second envelope sectionis inserted beneath them and receives no sudden jolt as the grid andcassette, inserted into the pouch, then pass beneath them, because thethickness of the stiffening member adjacent the common edge approximatesthe thickness of the grid and cassette within the pouch on the otherside of the common edge.

After exposure to X-rays, the cassette or grid and cassette may beremoved from beneath the patient just as easily as they were inserted.

The X-ray image may need to be taken either in landscape or in portraitformat. To readily enable this, the first envelope section is preferablyformed so as to define two pouches alongside each other with a commonwall extending therebetween, one said pouch being dimensioned so as toaccept the grid and cassette in landscape position and the other pouchbeing dimensioned to allow insertion of the grid and cassette inportrait position.

It will be appreciated that with this configuration, the landscape pouchor the portrait pouch will be uppermost depending upon which side of thedevice is uppermost. The respective landscape and portrait pouches maybe identified on the outer surface of the envelope on its two sides bygenerally “L-shaped” markings (lead-free to maintain radiotranslucency)identifying the corners of the cassette when inserted into thecorresponding pouch. This readily enables a radiographer to choose whichway up he wishes to use the device and insert the cassette or grid andcassette into the appropriate pouch. The pouches may suitably be closedby hook-and-loop fastenings, such as those sold under the VELCRO®Trademark.

In a second and alternative aspect of this invention, there is provideda radiographic grid and X-ray cassette mounted within a device forpositioning the grid and cassette beneath a patient lying upon a bed orother support to enable an X-ray image of a portion of the patient to betaken; the device comprising: a plastics envelope formed of a materialthat is both substantially radiotranslucent and impervious to water orother biological fluids; the envelope defining first and second envelopesections separated from each other by a common edge; the first envelopesection being generally rectangular in configuration and defining anopenable pouch in which the radiographic grid and X-ray cassette arereceived; and the second envelope section having a stiffening membertherein, the second envelope section having its greatest width alongsaid common edge and narrowing to a minimum width at its edge furthestfrom said common edge, and the stiffening member within the secondenvelope section being generally wedge shape in section, whereby thesecond envelope section has a thickness that tapers from a maximumthickness approximating the thickness of the radiographic grid and X-raycassette at its greatest width adjacent the common edge to a minimumthickness at said furthest edge.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is hereinafter more particularly described by way ofexample only with reference to the accompanying drawings, in which:

FIG. 1 is a plan view of an embodiment of positioning device inaccordance with this invention;

FIG. 2 is a partial sectional view taken along the lines II—II in FIG.1;

FIG. 3 shows part of the reverse plan view for an alternative andpreferred embodiment of the device;

FIG. 4 is an underneath plan view of another embodiment of the device;

FIG. 5 is an enlarged sectional view taken along the line V—V in FIG. 4;

FIG. 6 is an underneath plan view of yet another embodiment of thedevice; and

FIG. 7 is a side elevational view of the embodiment of FIG. 6.

DESCRIPTION OF PREFERRED EMBODIMENTS

As can best be seen from FIG. 1, a positioning device according to thepresent invention for use in radiography to position an X-ray cassetteor a radiographic grid and X-ray cassette beneath a patient lying upon abed or other support to enable an X-ray image of a portion of thepatient to be taken essentially comprises a plastics envelope 1 definingfirst and second envelope sections 2,3 separated from each other by acommon edge 4. As can be seen from FIG. 1, the first envelope section 2is generally rectangular in configuration while the second envelopesection 3 has the shape of a trapezium or truncated triangle the widthof which narrows from edge 4 to a minimum width at its furthest edge 5,where a handle 6 formed of cotton or other fabric tape is attached.Although the edges of envelope section 3 are shown as straight lines,they could be curved. The envelope sections are sealed from each otheralong the common edge 4 and also sealed along their remaining edges 5,7, 8, 9 and 10, leaving only edge 11 of section 2 open, in effectdefining a pouch.

The pouch is dimensioned to receive a conventional X-ray cassette aloneor a radiographic grid and X-ray cassette, for example a “35×43” gridand cassette designed to take chest or pelvic X-ray images with adimension of the order of 35 cm×43 cm. Outside surface 12 of section 2has lead-free L-shaped corner position markers 13 thereon indicating theposition of such a cassette or grid and cassette when fully insertedinto the pouch. The pouch is releasably closed by means of co-operatinghook-and-loop fastening strips 14 adhered to the inside surfaces of theplastics envelope 1.

Sealed within envelope section 3 is a stiffening member 15 which isgenerally wedge-shaped in section, as shown in FIG. 2 having itsgreatest thickness adjacent the common edge 4 and its narrowestthickness adjacent the furthest edge 5. Stiffening member 15 may beprovided as a fully rigid board but preferably has some flexibility toaid in inserting the device, leading with edge 5, beneath a patientlying upon a bed or other support, for example by separating a top sheetfrom its under sheet and sliding the device between the two sheets. Ifthe stiffening member 15 has some flexibility, this will be greatestadjacent edge 5 where it is at its thinnest and least adjacent edge 4.As the device is pushed beneath the patient, the patient will feel verylittle but is slowly raised by the thickness of section 3 with itsstiffening member 15 therewithin until the patient is raisedsufficiently by the time edge 4 passes underneath the patient for thegrid and cassette 16 within envelope section 2, having a thickness(generally of 25 mm when both grid and cassette are used) approximatingthe greatest thickness of stiffening member 15, to pass beneath thepatient without significantly jarring or jolting their pelvis or spine.

As will be apparent from the positions of L-shaped corner indications13, the pouch defined by envelope section 2 is designed to receive gridand cassette 16 with the longer of their edges parallel to and adjacentthe common edge 4. Depending upon the purpose for which an X-ray imageis to be taken, it may be desirable to take that image either inportrait or landscape format. To allow for this, in an alternative andpreferred embodiment, as illustrated by FIG. 3, envelope section 2suitably provides two separate pouches alongside each other by having aninternal medial wall 17 attached internally of envelope section 2 to thewall 18 opposite wall 12, at least along edges 19. As will be seen fromthe corresponding corner markings 13 a on wall 18, the second pouch sodefined within envelope section 2 allows the grid and cassette to beinserted only in the opposite configuration with their shorter edgeadjacent common edge 4.

Plastics material for envelope 1 must necessarily be substantiallyradiotranslucent (transparent to X-rays) and should also be imperviousto water and other biological fluids such as blood and urine. Thesurface of the envelope can be readily cleaned to meet the hygienestandards required in hospitals. A suitable material is heavyweightpolyvinylchloride. Preferably this material is given a low-frictionvarnish coating to enable the device to slip easily between two sheetson a bed. Coated PVC of this kind is available from Lows Ltd of Dundee.A suitable material for the stiffening member is a PVC plastics foam,but other cardboard or plastics members could be used, if formed withthe appropriate profile.

All the edges of the envelope sections that are required to be sealedare suitably plastics welded under conditions of heat and pressuresufficient to soften and join the edges of the plastics sheetsconcerned.

The material employed for the envelope and/or a low-friction coatingapplied to should alone be sufficient to enable the device to be slidbeneath a patient. However, this ability to insert the device beneath apatient can be enhanced as explained below.

As shown in FIGS. 4 and 5, a number of roller ball units 20, here four,one at each corner, are mounted on the bottom surface 21 of the firstenvelope section 2. Each roller ball unit 20 comprises a ball 22 freelyrotatable within a cage 23, the opening 24 of which is smaller than thediametric cross-section of the ball. The balls rotate as the device ispulled beneath a patient. The balls may be of steel, but are preferablyof Nylon (for example Nylon 11), which is effectively self-lubricating.

In a variation, not illustrated, the rollers are replaced by smallwheels, for example castors, or rollers.

In the alternative arrangement illustrated in FIGS. 6 and 7, an endlesstrack 25 is mounted beneath the device, the track passing aroundpulleys, here rollers 26, 27 suitably made of steel or Nylon, as thedevice is pulled beneath a patient. The rollers are rotatable on axles28 supported from the underside 21 of the first envelope section 2.Track 25 is suitably formed as an endless belt or as a length of beltingjoined at its ends, in either case being of a material with a relativelyhigh co-efficient of friction (for example: rubber) to impart agenerally non-slip surface to the track.

In a variation, not illustrated, rather than a single track 24 acrossthe greater part of the width of the underside 21 of envelope section 2,separate tracks may be provided adjacent the marginal side edges ofunderside 21, rather in the manner of tank tracks, and further pulleysmay be mounted intermediate the end pulleys to aid in support of thetrack at such intermediate positions.

As will be appreciated, any arrangement with auxiliary travel means suchas roller balls, wheels, rollers or tracks must necessarily be thickerthan would be the case for a corresponding device without such auxiliarytravel means. The greater the thickness, the more the patient is movedon insertion of an X-ray cassette beneath them. Accordingly,arrangements without auxiliary travel means will usually be preferredexcept where the patient is unusually heavy or the surface on which theyare lying is not even, and may not be a bed. Devices in accordance withthe embodiments of FIGS. 4 to 7 are particularly useful in veterinarypractice, where—for example—an animal may need to be X-rayed while lyingon the floor.

1. A positioning device for use in radiography to position an X-raycassette or a radiographic grid and X-ray cassette beneath a patientlying upon a bed or other support to enable an X-ray image of a portionof the patient to be taken; the device comprising: a plastics envelopeformed of a material that is both substantially radiotranslucent andimpervious to water or other biological fluids; the envelope definingfirst and second envelope sections separated from each other by a commonedge; the first envelope section being generally rectangular inconfiguration and defining an openable pouch dimensioned to receive anX-ray cassette or radiographic grid and X-ray cassette therein; and thesecond envelope section having a stiffening member therein, the secondenvelope section having its greatest width along said common edge andnarrowing to a minimum width at its edge furthest from said common edge,and the stiffening member within the second envelope section beinggenerally wedge shape in section, whereby the second envelope sectionhas a thickness that tapers from a maximum thickness approximating thethickness of a radiographic grid and X-ray cassette at its greatestwidth adjacent the common edge to a minimum thickness at said furthestedge.
 2. A device according to claim 1, wherein the said furthest edgeis provided with a handle formed of tape, the handle being graspablefrom the opposite side of a bed or support when the said furthest edgeis slid beneath a patient from one side of the said bed or support,thereafter enabling the device with an X-ray cassette or a radiographicgrid and X-ray cassette within the said pouch to be pulled into positionbeneath the patient.
 3. A device according to claim 1, wherein the outersurface of the first envelope section is provided with lead-freemarkings, identifying the position of an X-ray cassette or radiographicgrid and X-ray cassette fully inserted into said pouch to aid in correctpositioning.
 4. A device according to claim 1, wherein the firstenvelope section defines two pouches therein, one in landscapeorientation and the other in portrait orientation for the X-ray image.5. A device according to claim 4, wherein space within the firstenvelope section is divided by a substantially medial wall to providetwo pouches alongside each other, one associated with each side of thedevice.
 6. A device according to claim 5, wherein the opposite outersurfaces of the first envelope section are each provided with lead-freemarkings, identifying the position of an X-ray cassette or radiographicgrid and X-ray cassette when fully inserted into the immediatelyunderlying pouch, so that one side of the device has markings indicatingits use for landscape images, and the other side of the device hasmarkings indicating its use for portrait images.
 7. A device accordingto claim 1, wherein the stiffening member is at least partially flexiblerather than being essentially rigid, its resistance to flexureincreasing from said furthest edge towards said common edge.
 8. A deviceaccording to claim 1, wherein the underside of the first envelopesection is provided with auxiliary travel means adapted to assist inlocation of the first envelope section beneath a patient.
 9. A deviceaccording to claim 8, wherein the auxiliary travel means comprise aplurality of roller balls.
 10. A device according to claim 8, whereinthe auxiliary travel means comprise at least one endless trackconstrained to pass around pulleys.
 11. A radiographic grid and X-raycassette mounted within a device for positioning the grid and cassettebeneath a patient lying upon a bed or other support to enable an X-rayimage of a portion of the patient to be taken; the device comprising: aplastics envelope formed of a material that is both substantiallyradiotranslucent and impervious to water or other biological fluids; theenvelope defining first and second envelope sections separated from eachother by a common edge; the first envelope section being generallyrectangular in configuration and defining an openable pouch in which theradiographic grid and X-ray cassette are received; and the secondenvelope section having a stiffening member therein, the second envelopesection having its greatest width along said common edge and narrowingto a minimum width at its edge furthest from said common edge, and thestiffening member within the second envelope section being generallywedge shape in section, whereby the second envelope section has athickness that tapers from a maximum thickness approximating thethickness of the radiographic grid and X-ray cassette at its greatestwidth adjacent the common edge to a minimum thickness at said furthestedge.